Blood drop generation devices are well known in the art for providing blood samples which are used in performing various blood tests for preventative medicine and medical diagnosis. Such devices operate by creating a small puncture or incision in the skin of the fingertip or other area of the body such as the foot, arm, or leg.
Since most blood drop generation devices employ a lancet-like structure for puncturing or incising the skin, blood drop generation devices are often referred to as lancet devices. Many prior art lancet devices employ spring loaded cutting blades which are enclosed within a casing or housing. These devices are operated by placing the housing of the device against the skin and triggering the spring loaded cutting blade in the device. The potential energy stored within the spring accelerates the blade through an aperture in the housing and creates a uniform puncture or incision in the skin. The structural configuration of these devices enable the puncture or incision in the skin to be made in a controlled manner in terms of location, size, depth, and sterility. Since the blade is concealed within the housing, the patient is unable to view the blade prior to, or during the puncturing of the skin which reduces the patient's anxiety. Further, most recent designs of lancet devices include means for retracting the blade back into the housing after the puncture or incision has been made. Such a safety feature advantageously reduces the probability of a disease being spread through contact with the used blade of the device. This is an important feature since, deadly viruses such as AIDS and Hepatitis can spread from accidental punctures obtained from lancets used previously on an infected patient.
As already mentioned, the structural configuration of a lancet device enables it to puncture or incise the skin in a controlled manner in terms of location, size and depth. Devices which puncture the skin employ cutting blades which plunge perpendicularly into the skin to produce a skin incision of a predetermined depth. Such lancets are exemplified in U.S. Pat. No. 5,133,730 to Biro. In U.S. Pat. No. 5,133,730, a sharp blade is provided on a spring biased pivot arm which moves the blade out through an orifice in the lancet housing and then retracts the blade back into the housing. Although the blade is positioned on a pivot arm, the blade is directed perpendicularly, into the surface of the skin. The shape of the blade helps the blade enter the skin and make the needed incision. Other lancet devices that create plunge-type cuts are described in U.S. Pat. No. 3,760,809 to Cambell, Jr. and U.S. Pat. No. 5,395,388 to Schrage.
Lancet devices which incise the skin employ cutting blades which move in an arcuate motion or cutting blades which move simultaneously in a perpendicular and transverse motion. The lancet devices employing cutting blades that incise the skin in an arcuate manner are exemplified in U.S. Pat. No. 3,902,475 to Berg et al. The lancets in U.S. Pat. No. 3,902,475 produce skin incisions that vary in depth along the length of the incision. Consequently, in order to obtain a requisite incision depth of between 1 and 5 mm, such lancet devices must produce incisions that are relatively long and thus, less desirable.
The lancet devices employing cutting blades that incise the skin in a simultaneous perpendicular and transverse motion are capable of producing skin incisions which are uniform in depth along the entire length of the incision. Such a lancet device is described in U.S. Pat. No. 4,643,189 to Mintz. The simultaneous perpendicular and transverse motion of the cutting blade is accomplished by providing a unique cam configuration which controls the path of a pivoting arm that contains a cutting blade. The cutting blade is powered by a looped straight-arm torsion spring which is installed when the lancet device is assembled.